US2344494A - Method of coating glass thread - Google Patents

Description

Patented Mar. 21,

METHOD OF. COATING GLASS THREAD William M. Camp, Glen Ridge, N. J., asslgnor to The Clark Thread Company, Newark, N. J., a corporation of New Jersey No Drawing. Application March 14, 1940, Serial No. 823,987

1 Claim.

This invention relates to a novel and improved method of forming a thread of glass fibers or filaments. As known in the art, usually glass thread is formed of twisted filaments, each filament being extruded in a' continuous length. These filaments, however, can be made into short lengths, similar to cotton fibers, and spun into yarns, in a similar manner to that employed in the spinning of rayon stable fiber.

When glass filamentsare formed into thread, the result is a product which has certain advantages but which hascertainother very definite disadvantages. Among the disadvantages is that the thread is quite brittle, which renders it unsuitable for sewing purposes, particularly in sewing machines where the thread is subjected to sharp sudden flexing, especially where the machine is operated at high speed. This is the principal disadvantage which is overcome by the present invention.

For the sake of illustration, I may describe my invention as being practiced with a thread made of a large number of ends, for example fifteen ends, each of which in turnis formed of many fine filaments of glass fiber, these being twisted together to form a thread. As an example, glass yarn supplied by the manufacturer, known as 900/2, is plied fifteen times to make a sewing thread. a a

The thread thus formed is then run through a bath of rubber latex or some equivalent compound of rubber or other adhesive. For the sake of convenience, however, the material in the bath will be referred to as latex. The apparatusfor running the thread through the bath maybe any of the usual pieces of apparatus used for such purposes and needs no description.

After leaving the bath, the thread is then heated and compressed, preferably -by being passed through'a round hole in a heated die, the diameter of the hole being such that the wet thread in passing through it is compressed. By that arrangement, the latex is forced into the interior or the thread, between the fibers or filaments of which the thread is composed, and thus the thread is thoroughly impregnated with latex and a thin film of latex is formed over the outside surfaces thus protecting the fibers against abrasion. Preferably, the temperature of the die is kept at an ordinary flatiron temperature, say, about 350. By proceeding in this manne the latex coating is smoothed and burnished or "ironed.

- After the glass yarn has been impregnatedwith latex and run through the dies, the mate rial may then be placed in an oven and vul-' canized in the normal manner. In that case, a suitable vulcanizing agent may be incorporated into the latex prior to impregnation.

I have found that by the method which I have described above, I am able to producethread which is no longer brittle, but-which may be used as a sewing thread. At the same time the coating of latex which is provided on the thread is one which prevents glass filaments or fibers from cutting or wearing each other while it is being sewed into the cloth.

One of the other advantages of my method is that it makes it possible to make thread of any desired color. Ordinarily, glass thread has to be colored by coloring the glass from which it is formed, but this method limits the number 01' colors that can be obtained. However, with my method it is possible to incorporate in the latex any desired dyestufl which will give to the finished thread the desired color. There is practically no limit tothe number of colors which may thus be given to the finished product.

Since the invention has been found to be particularly useful with sewing thread, I have for convenience used the word thread in referring to the product, but by that term I do not intend to limit myself to any particular size of thread,

because the invention may be practiced equally well with materials which are usually referred to as yarn or cord. The word thread" therefore is used to cover any of such equivalent products:

I claim:

The method or treating glass fiber thread which comprises impregnating said thread with latex and then passing the impregnated thread through the orifice of a heated die, said orifice having a circular cross section less than the cross section of the thread and of suchdimensions that the thread is compressed during passage through said orifice, and heating the'impregnated thread while it is subjected to said pressure.

WIILIAM M. CAMP.